let $surQ := doc("survey.xml")/SURVEY/QUESTION/MCQUESTION
let $resQ := doc("responses.xml")/CLASS/STUDENT/RESPONSES/MCRESPONSE
for $surOption in doc("survey.xml")/SURVEY/QUESTION/MCQUESTION/CHOICE
where every $a in $resQ/ANSWER satisfies (data($surOption)!=data($a))
return <result>{$surOption/../../@questionID}{$surOption}</result>
